Michael Timmers, Sofie Pollin, Antoine Dejonghe, Liesbet Van der Perre, and Francky Catthoor Katholieke Universiteit (K.U.) Leuven IEEE Transactions on Vehicular Technology, TVT 2010 Page: 2 WMNL Introduction Conclusion Multichannel MAC protocol for CR networks (MMAC-CR) Multichannel MAC protocol for CR networks (MMAC-CR) Performance Evaluation Page: 3 WMNL Introduction Conclusion Multichannel MAC protocol for CR networks (MMAC-CR) Multichannel MAC protocol for CR networks (MMAC-CR) Performance Evaluation Page: 4 WMNL Defense Advanced Research Projects Agency (DARPA) Only 2% spectrum are used at a given time and location. Federal Communications Commission in the United States (FCC) 15%~85% of the licensed spectrum remains unused at a given time and location. White holes A more flexible allocation strategy could solve the spectrum scarcity problem. Page: 5 WMNL Cognitive Radio (CR) Networks Primary User (or Licensed User) Has a license to operate in a certain spectrum band. Secondary User (or Unlicensed User) Has no spectrum license. Additional functionalities are required to share the license spectrum band. Page: 6 WMNL Primary User (or Licensed User) Has a license to operate in a certain spectrum band. Secondary User (or Unlicensed User) Has no spectrum license. Hence, additional functionalities are required to share the license spectrum band. Page: 7 WMNL StandardPurpose IEEE SCC41 IEEE (TV channel) IEEE k Wi-Fi IEEE y MHz IEEE h WiMAX (License-exempt) Page: 8 WMNL Multichannel advantages over single-channel Reduce interference among users Increased network throughput Reduce the number of CRs affected by the return of PU Distributed controlled advantages over centrally controlled Reduces infrastructure cost Providing larger flexibility Providing larger robustness Page: 9 WMNL Recently, some MMAC-CRs have been proposed. Focused on CR performance rather than on protection of the Pus Not consider missed detections and false alarm Not consider energy efficiency Not handled the Hidden PU problem Require tight synchronization Focuses on single-hop networks PU A A B B C C Detectability Range Page: 10 WMNL Proposes a distributed multichannel MAC protocol for CR networks. Improve performance Protect the PUs from interference Decrease the energy cost Only requires less tight synchronization Multi-hop Page: 11 WMNL Introduction Conclusion Multichannel MAC protocol for CR networks (MMAC-CR) Multichannel MAC protocol for CR networks (MMAC-CR) Performance Evaluation Page: 12 WMNL C+1 channels are available for use None of these channels overlap One of the channels is a Common Control Channel (CCC) This channel is free of PU interference All radios are assumed to have an interface The interface is capable of dynamically switching their channel Dedicated for sensing purposes Communicating and sensing can be done in parallel on different channels Page: 13 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK DATA ACK Beacon Interval Licensed Channels ATIM-RES RTS CTS Page: 14 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON Control Channel Beacon Interval Licensed Channels Page: 15 WMNL E E 00:03 B B F F 00:01 D D 00:02 H H 00:03 C C 00:01 A A 00:02 I I G G 00:01 Page: 16 WMNL E E 00:03 B B F F 00:01 D D 00:02 H H 00:03 C C 00:01 A A 00:02 I I G G 00:01 00:02 00:01 Page: 17 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON Licensed Channels Control Channel Beacon Interval Initialization Update Page: 18 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON Control Channel Beacon Interval Update Initialization Licensed Channels Page: 19 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON Control Channel Beacon Interval Initialization Update Licensed Channels Page: 20 WMNL Spectral Image of Pus (SIP) Channel A B C D E F 0 No PU is active 1 A PU is active 2 The spectral image is uncertain A Ch1 Ch4 B C D F E Page: 21 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel Beacon Interval Licensed Channels Scan Result Packet Page: 22 WMNL Spectral Image of Pus (SIP) Channel A Ch1 Ch4 B C D F E A B C D E F [ 0,1,1,1,1,1 ] [ 0,1,1,0,1,1 ] [ 1,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities Page: 23 WMNL Spectral Image of Pus (SIP) Channel A Ch1 Ch4 B C D F E SRP Time A B C D E F A E F [ 0,1,1,1,1,1 ] [ 0,1,1,0,1,1 ] [ 1,1,1,0,1,1 ] [ 0,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities Page: 24 WMNL Spectral Image of Pus (SIP) Channel A Ch1 Ch4 B C D F E A B C D E F [ 0,1,1,1,1,1 ] [ 0,1,1,0,1,1 ] [ 1,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities [ 0,1,1,0,1,1 ] Page: 25 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK Beacon Interval Licensed Channels ATIM-RES Page: 26 WMNL A Ch1 Ch4 B C D F E [ 0,1,1,1,1,1 ] [ 0,1,1,0,1,1 ] [ 1,1,1,0,1,1 ] [ 0,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities Hidden region of C Hidden region of D Page: 27 WMNL C D [ 0,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities ATIM[0,1,1,0,1,1]ATIM-ACK (Ch2)ATIM-RES (Ch2) A B F E [ 0,1,1,1,1,1 ] [ 1,1,1,0,1,1 ] Page: 28 WMNL C D [ 0,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities ATIM[0,1,1,0,1,1] Secondary users Channel Load (SCL) Channel A B C D E F ATIM-ACK (Ch2)ATIM-RES (Ch2) A B F E [ 0,1,1,1,1,1 ] [ 1,1,1,0,1,1 ] Page: 29 WMNL Secondary users Channel Load (SCL) Channel A B C D E F C D [ 0,1,1,0,1,1 ] [ Ch1,Ch2,Ch3,Ch4,Ch5,Ch6 ] Spectral Opportunities ATIM[1,1,1,0,1,1] ATIM-ACK (Ch1)ATIM-RES (Ch1) A B F E [ 0,1,1,1,1,1 ] [ 1,1,1,0,1,1 ] Ch2 Page: 30 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK Beacon Interval Licensed Channels ATIM-RES DATA ACK RTS CTS Page: 31 WMNL Spectral Image of Pus (SIP) Channel A B C D E F 0 No PU is active 1 A PU is active 2 The spectral image is uncertain A Ch1 Ch4 B C D F E Page: 32 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK Beacon Interval Licensed Channels ATIM-RES Page: 33 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK Beacon Interval Licensed Channels ATIM-RES Page: 34 WMNL Packet Type PriorityBackoff Time ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK Beacon Interval ATIM-RES BEACON SRP ATIM ATIM-ACK ATIM-RES Beacon SRP ATIM Handshakes High Low [0, CW / 2) [CW / 2, CW) Page: 35 WMNL F B G E J CA KI H D L Ch1 Ch2 SRP A I H Page: 36 WMNL F B G E J CA KI H D L Ch1 Ch2 SRP A I H ,2 Ch2 Page: 37 WMNL F B G E J CA KI H D L Ch1 Ch2 SRP A I H ,2 ATIM-RES (Ch2) ATIM ATIM-ACK (Ch2) K SRP Page: 38 WMNL F B G E J CA KI H D L Ch1 Ch2 SRP A I H ,2 ATIM-RES (Ch3) ATIM ATIM-ACK (Ch3) K SRP Page: 39 WMNL ATIM Window (Fast Scan) DATA Window (Fine Scan) BEACON SRP Control Channel ATIM ATIM-ACK Beacon Interval Licensed Channels ATIM-RES DATA ACK RTS CTS Page: 40 WMNL ATIM WindowDATA Window A ATIM Window B C Time BEACON ATIM ATIM-ACK DATA ACK Doze State ATIM-RES RTS CTS B C A C Page: 41 WMNL Introduction Conclusion Multichannel MAC protocol for CR networks (MMAC-CR) Multichannel MAC protocol for CR networks (MMAC-CR) Performance Evaluation Page: 42 WMNL Simulation Parameters Simulatorns-2 (version 2.29) Datarate24Mbps CWmin15 CWmax1023 SIFS 16 s t ATIM 10ms t BI 100ms Fast sensing1ms Fine sensing25ms CRs deploymentRandomly PNs deploymentRandomly Page: 43 WMNL Power Table of IMEC SDR AnalogDigital Doze0mW10mW Idle (Fast Sensing) 120mW11mW131mW Receive (Fine Sensing) 120mW370mW490mW Transmit600mW300mW900mW Page: 44 WMNL Performance metrics Channel Vacate Time Total Interference Time Time and Energy Spent Througuput Page: 45 WMNL Single-hop Scenario Parameter 4 PNs 20 CRs (10 are communicating) CRs sending 150 packet/s 5 channel 80m 80 m Page: 46 WMNL Single-hop PU channel statesCR channel states Page: 47 WMNL Single-hop Channel Vacate TimeTotal Interfered Time Page: 48 WMNL Single-hop Time and Energy cost Page: 49 WMNL Single-hop CR Performance Page: 50 WMNL Multi-hop Scenario Parameter 4 PNs 2 traffic streams (150 packet/s) Interference range 350m 5 channel 500m 500 m Page: 51 WMNL Multi-hop Channel Vacate TimeTotal Interfered Time Page: 52 WMNL Introduction Conclusion Multichannel MAC protocol for CR networks (MMAC-CR) Multichannel MAC protocol for CR networks (MMAC-CR) Performance Evaluation Page: 53 WMNL Proposes a distributed multichannel MAC protocol for CR networks. Improve performance Protect the PUs from interference Decrease the energy cost Only requires less tight synchronization Multi-hop Page: 54 WMNL Page: 55 WMNL